| 摘要 |
PROBLEM TO BE SOLVED: To provide a liquid chemical injection control unit capable of detecting abnormality inexpensively, easily and accurately even if the injection amount of a liquid chemical is controlled so as to be changed over a wide range in response to the fluctuations in the flow velocity of a fluid to be treated, or the like. SOLUTION: The liquid chemical injection control unit is equipped with a target injection amount operation means 8 for operating and leading out the target injection amount SV of the liquid chemical on the basis of the detected flow rate of tap water due to a flowmeter 1b and the target concenteration of the liquid chemical, an injection amount control means 9 for outputting the drive control signal MV corresponding to a drive frequency signal to an inverter 10 being the drive circuit of a chemical injection pump 5 so that the detected injection amount PV of the liquid chemical injected by the liquid chemical injection pump 5 and detected by a liquid chemical flowmeter 4b becomes the target injection amount SV, and a monitor means 11 for self-diagnosing the operation state of a liquid chemical injection device on the basis of the drive control signal MV, the detected injection amount PV and table data. COPYRIGHT: (C)2005,JPO&NCIPI
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